1,251 research outputs found

    Influence of QED Corrections on the Orientation of Chiral Symmetry Breaking in the NJL model

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    We study QED corrections to chiral symmetry breaking in the Nambu--Jona-Lasinio (NJL) model with two flavors of quarks. In this model, the isospin symmetry is broken by the differences between the current quark masses and the electromagnetic charges of the up and down quarks. To leading order in the 1/N expansion, we calculate the effective potential of the model with one-loop QED corrections at finite temperature. Evaluating the effective potential, we study the influence of the isospin symmetry breaking on the orientation of chiral symmetry breaking. The current quark mass plays an essential role in maintaining the orientation of the chiral symmetry breaking. If the average of the up and down quark masses is small enough, we find a phase in which the pion field has non-vanishing expectation value and dynamical CP violation takes place.Comment: 22 pages, 13 figures; added discussion about pion mass differenc

    Color Superconductivity and Radius of Quark Star in Extended NJL Model by Using the Dimensional Regularization

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    A radius of a dense star on the color superconducting phase is investigated in an extended NJL type model with two flavors of quarks. Since the model is non-renormalizable, the results depend on the regularization procedure. Here we apply the dimensional regularization and evaluate the radius of a dense star. Evaluating the TOV equation, we show the relationship between mass and radius of the dense star in the dimensional regularization.Comment: 4 pages.To appear in the proceedings of 7th Workshop on Quantum Field Theory Under the Influence of External Conditions (QFEXT 05), Barcelona, Catalonia, Spain, 5-9 Sep 2005. References are ad

    Low scale Seesaw model and Lepton Flavor Violating Rare B Decays

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    We study lepton flavor number violating rare B decays, b→slh±ll∓b \to s l_h^{\pm} l_l^{\mp}, in a seesaw model with low scale singlet Majorana neutrinos motivated by the resonant leptogenesis scenario. The branching ratios of inclusive decays b→slh±llˉ∓ b \to s l_h^{\pm} \bar{l_l}^{\mp} with two almost degenerate singlet neutrinos at TeV scale are investigated in detail. We find that there exists a class of seesaw model in which the branching fractions of b→sτμ b \to s \tau \mu and τ→μγ\tau \to \mu \gamma can be as large as 10−1010^{-10} and 10−910^{-9} within the reach of Super B factories, respectively, without being in conflict with neutrino mixings and mass squared difference of neutrinos from neutrino data, invisible decay width of ZZ and the present limit of Br(μ→eγ)Br(\mu \to e \gamma).Comment: 19 pages, 6 figure

    Cosmological Family Asymmetry and CP violation

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    We discuss how the cosmological baryon asymmetry can be achieved by the lepton family asymmetries of heavy Majorana neutrino decays and they are related to CP violation in neutrino oscillation, in the minimal seesaw model with two heavy Majorana neutrinos. We derive the most general formula for CP violation in neutrino oscillation in terms of the heavy Majorana masses and Yukawa mass term. It is shown that the formula is very useful to classify several models in which e−e-, μ−\mu- and τ−\tau-leptogenesis can be separately realized and to see how they are connected with low energy CP violaton. To make the models predictive, we take texture with two zeros in the Dirac neutrino Yukawa matrix. In particular, we find some interesting cases in which CP violation in neutrino oscillation can happen while lepton family asymmetries do not exist at all. On the contrary, we can find e−e-, μ−\mu- and τ−\tau-leptogenesis scenarios in which the cosmological CP violation and low energy CP violation measurable via neutrino oscillations are very closely related to each other. By determining the allowed ranges of the parameters in the models, we predict the sizes of CP violation in neutrino oscillation and ∣Ve3MNS∣|V_{e3}^{MNS}|. Finally, the leptonic unitarity triangles are reconstructed.Comment: 22 pages, 9 figures A figure caption correcte

    HIP MOMENT PROFILES DURING CIRCLES IN SIDE SUPPORT AND IN CROSS SUPPORT ON THE POMMEL HORSE

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    The purpose of this study was to analyze the hip moment profiles during Circles and to assess how gymnasts modulate their technique depending on different orientation on the pommel horse. Circles in side support and in cross support performed by six gymnasts were captured using Qualysis motion capture system. Hip joint moments were computed with the assumption that the total leg was a single rigid body. The results implied that the lateral-flexion movement at the hip joint was closely related to the important technique of both types of Circles. Cross-Circles were characterized by the greater flexor moment throughout a Circle and the smaller lateral flexor moment in the rear support phase

    High density quark matter in the NJL model with dimensional vs. cut-off regularization

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    We investigate color superconducting phase at high density in the extended Nambu--Jona-Lasinio model for the two flavor quarks. Because of the non-renormalizability of the model, physical observables may depend on the regularization procedure, that is why we apply two types of regularization, the cut-off and the dimensional one to evaluate the phase structure, the equation of state and the relationship between the mass and the radius of a dense star. To obtain the phase structure we evaluate the minimum of the effective potential at finite temperature and chemical potential. The stress tensor is calculated to derive the equation of state. Solving the Tolman-Oppenheimer-Volkoff equation, we show the relationship between the mass and the radius of a dense star. The dependence on the regularization is found not to be small for these phenomena in the color superconducting phase.Comment: 10 pages, 11 figures; a few points corrected and references adde

    Modeling Interaction of Fluid and Salt in an Aquifer/Lagoon System

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    Auther Posting. ©The Authers 2009 The full text of this article is published in GROUND WATER, 47, 1, 35-48. It is available online from Blackwell-Synergy at https://doi.org/10.1111/j.1745-6584.2008.00482.xArticleGROUND WATER. 47(1):35-48 (2009)journal articl
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